#3DS v3 DXF Weird Imports
12 messages in this thread
Hi folks!
Does anyone have problems trasferring 3DFACE entities from AutoCAD r12c2
to 3D Studio via DXF? I've set up a simple series of faces to begin modeling
the interior of an office in AutoCAD. The faces are all vertical walls – no
goofy slanted surfaces or anything, and at 90 degrees to each other. When I
export the entities (using the DXFOUT, Entities option) and merge or load them
into the current project, the entities _will_ show up. I can assign materials
to the faces like normal, set up cameras and lights – no problem. When I
actually render the scene, though, half of the entities do not show up. Any
suggestions about my problem? Thanks for any assistance!
Bill
Bill
The problem is with face normals. You have to Select/Face to get the offending
faces, then use Modify/Object/Normals/Face Flip. Or, you can turn the Force
2-Sided button on in the Render Still Image dialog box, or, better yet, create
a material with the 2 sided button on the Material Editor.
Good luck
TedB
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Ted,
Thanks for all the info. Right now the model is pretty simple, so I'll
try forcing the rendering to 2-sided, but we'll have to see as I try to add
more information.
Bill
Bill
Download a file from the forum library called Optimiz.zip. It is a full
working version of the Yost Plug-in with face normal flipping capability. It
won't let you save the file, but it would give you a very good idea of exactly
which faces were causing the problem, especially on complex files.
Have fun.
TedB
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Just do what Ted told you, there is nothing more to it, in some cases the only
solution is to do 2sided rendering, or you might be working for days to work
out which faces point in the right direction and thus adjusting the ones which
are wrong.
Otherwise you should always draw your 3D face counter clockwise in AutoCAD seen
from the direction that it is visible.
Just lets say this: 3DS tries to increase rendering speed by only calculating
the positive face side of a 3Dface, so if the normal points in the wrong
direction you will not see it.
Either you adjust that face as Ted says or you do 2 sided rendering where all
sides of a face are calculated.
Christophe
Christopher,
Yeah, I'll have to pay attention as I create the stuff in AutoCAD. Now
if I use the AutoCAD 3D* commands to create elements and then export those via
DXF, will the appear correct, from all sides, within 3DS? Does the new v4
"fix" this problem, or is it more getting into the correct habit when creating
3D elements within CADD packages?
Bill
R4 does not fix this and I'll doubt you will ever create a model of a certain
complexity in any CAD program that will import perfectly, it will nearly always
need some fixing if you want to get rid of 2sided rendering, however to me this
has not been a big problem so far. Mostly if I have complex models I simply
take into account that 2sided rendering is the only solution, rather let the
machine spend a few extra hours or days then me fixing all the normals, might
also take days when I do architectural models in AutoCAD and import them to 3DS
and then fix all the normals.
Christophe
Hi Christophe,
<< might also take days when I do architectural models in AutoCAD and import
them to 3DS and then fix all the normals. >>
Is this using Optimize to help identify and flip the normals?
jonas[adesk]
Yes this is using optimize, models gets so complex that even optimize does not
help me out always, for small models like cars etc optimize is wonderful, it
once helped me reduce a 3MB file to about 1.3 MB, just by reducing to complex
models in a 3D.
But the flip normals possibilities for large objects are still difficult, one
has to consider why one needs it, sometimes it is to time consuming certainly
for stills to adjust all normals and then rendering. 2sided is much faster
then.
I'd have to split the objects into smaller objects to succeed however this is
not always possible.
However one thing that would help me if I could have the optimize window full
screen, this would be a great help.
Christophe
In addition to Ted's good advice, here are some observations I have made for
best results when importing a DXF from ANY application:
1) In the "other" application, save the different parts of your objects to
different layers.
2) When importing to 3DS, derive objects from Layers. Do not Weld on import.
Do not Unify normals on Import.
3) Once the object is imported, you can weld it by selecting all of the faces
in a single object and using Modify/Vertex/Weld.
4) You can then try to Unify the normals by using Surface/Normals/Object
Unify. Some manual clean up may be required as per Ted's advice.
Good luck.
— James — MAP —
James,
I'll try and do that. My last attempt at importing everything used
separate layers for each group of entities, which I exported to separate DXF
files. I'll bring them in without "welding" and "unifying" and see what
happens. Thanks!
Bill
Bill,
Before you do a Surface/Normals/Object Unify make sure that the object doesn't
have multiple elements in it. If it doesn't then ObjectUnify will usually fix
your problem. If the object has multiple elements, ObjectUnify can make things
worse. The reason is that ObjectUnify has to determine what is inside and what
is outside the object. If you have multiple elements, you have multiple
insides and that can confuse 3DS.
Most commands in AutoCAD will produce an object that is either all normal or
all reversed and for these objects a simple Surface/Normals/Object Flip will
do. If you have been building manually with 3Dfaces, then you will need Object
Unify. After a while you get in the habit of counterclockwise faces and make
fewer mistakes. Of that type anyway<g>.
Terry Gilbert
Forcade & Associates